Picture frame



FIG. 1 is a front perspective view of a picture frame according to my design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is an end elevational view thereof; and,

FIG. 5 is a rear elevational view thereof. 

The ornamental design for a picture frame, as shown and described. 